THE forthcoming Vatican document on gays in seminaries will unleash a wrenching debate about Catholicism and homosexuality, but one thing it is certain not to mean is that in the future there will be no gays in the priesthood. The continued presence of gays in the priesthood will be the product not just of difficulties in enforcement, or the dishonesty of potential candidates, but also of design.

Although this is a difficult point for many Anglo-Saxons to grasp, when the Vatican makes statements like "no gays in the priesthood," it doesn't actually mean "no gays in the priesthood." It means, "As a general rule, this is not a good idea, but we all know there will be exceptions."

Understanding this distinction requires an appreciation of Italian concepts of law, which hold sway throughout the thought world of the Vatican. The law, according to such thinking, expresses an ideal. It describes a perfect state of affairs from which many people will inevitably fall short. This view is far removed from the typical Anglo-Saxon approach, which expects the law to dictate what people actually do.

While Italians grumble about lawlessness, fundamentally they believe in subjectivity. Anyone who's tried to negotiate the traffic in Italian cities will appreciate the point. No law, most Italians believe, can capture the infinite complexity of human situations, and it's more important for the law to describe a vision of the ideal community than for it to be rigidly obeyed. Italians have tough laws, but their enforcement is enormously forgiving. Not for nothing was their equivalent of the attorney general's office once known as the Ministry of Justice and Grace.

The British historian Christopher Dawson has described this as the "erotic" spirit of cultures shaped by Roman Catholicism. Catholic cultures are based on the passionate quest for spiritual perfection, Dawson writes, unlike the "bourgeois" culture of the United States, which, shaped by Protestantism and based on practical reason, gives priority to economic concerns. As one senior Vatican official put it to me some time ago, "Law describes the way things would work if men were angels."

This value system means that while Vatican officials often project a stern moral image on the public stage, in intimate settings they can be strikingly patient and understanding. Policymakers in the Vatican tend not to get as worked up as many Americans by the large numbers of Catholics in the developed world who flout church regulations on birth control, for example. It's not that Vatican officials don't believe in the regulations. Rather, they believe the very nature of an ideal is that many people will fail to realize it.

Of course, one can debate whether a ban on birth control, or on gays in seminaries, ought to be the ideal. The point is that although Vatican officials will never say so out loud, few actually expect those rules to be upheld in all cases.

Some in the Anglo-Saxon world see this as a form of hypocrisy: the church apparently issues laws while winking at disobedience. But Vatican officials view it instead as a realistic concession to fallen human nature.

On background, some such officials have said that the point of the forthcoming document is to challenge the conventional wisdom in the church, which holds that as long as a prospective priest is capable of celibacy, it doesn't matter whether he's gay or straight. Vatican policymakers and some American bishops believe that's naïve. In an all-male environment, they contend, a candidate whose sexual orientation is toward men faces greater temptations and hence a greater cause for concern.

That's a debatable proposition, but it does not add up to an absolute conviction that no gay man should ever be ordained a priest. Rather, it means that bishops should take a hard look at such candidates, but in the end, they'll still use their best judgment.

Those determined to apply this decree in uncompromising fashion will be able to do so. But while the Catholic priesthood of the future may include fewer homosexuals - and it will certainly have fewer gay seminarians and priests willing to speak openly about their situation - it will not be "gay free."

On the ground, as bishops and seminary teams make decisions, many will still draw on that classic bit of Italian clerical casuistry: "If the pope were here, he would understand."

John L. Allen Jr. is the Vatican correspondent for National Catholic Reporter.